Molecular sieves are a commercially important class of crystalline materials. They have distinct crystal structures with ordered pore structures which are demonstrated by distinct X-ray diffraction patterns. The crystal structure defines cavities and pores which are characteristic of the different species.
Molecular sieves identified by the International Zeolite Association as having the framework type CHA are known. For example, the aluminosilicate molecular sieve known as SSZ-13 is a known crystalline CHA material. U.S. Pat. No. 4,544,538 discloses SSZ-13 and its synthesis using N-alkyl-3-quinuclidinol, N,N,N-trialkyl-1-adamantammonium cations and/or N,N,N-trialkyl-exoaminonorbornane as a structure directing agent (“SDA”).
SSZ-13 is generally synthesized commercially using N,N,N-trimethyl-1-adamantammonium cation as a structure directing agent. However, this SDA is costly, which makes the synthesis of SSZ-13 using this SDA costly. This cost can limit the usefulness of SSZ-13 in commercial processes. Consequently, there has been significant interest in finding alternative, less expensive structure directing agents for the synthesis of SSZ-13.
It has now been found that pure phase aluminosilicate molecular sieves having the CHA framework type can be prepared using a trimethylphenylammonium cation as a structure directing agent.